the first technology of its kind... mom and dad, i have great news. is now providing answers families need. siemens. answers. >> bret: live in watertown, massachusetts, the hunt continues for 19-year-old dzhokhar tsarnaev. his brother tamerlan tsarnaev died overnight in a shootout. bring in the special panel tonight leon aaron is resident scholar and director of russian studies at the american ernesto prize institute author of the "roads to the temple and ideals and russian revolution." retired general jack keane and syndicated columnist charles krauthammer. okay, charles, you have been watching all of this. thoughts on the day and what you've heard? >> well, i think all of us don't want to pre-judge but i think the real question is the motive. and right now the evidence very strongly points so self-radicalized young men acting in the name of jihad. two kind of chechen terrorism. there is nationalist and religious. nationalists ones who are in chechnya fighting against the russians in a long, drawn out war twice suppressioned by russia and in response